隧道开挖对既有桥梁桩基承载力影响数值分析

依托成都地铁13号线隧道近距离穿越娇子立交桥桩基工程,建立有限元模型,研究隧道开挖对于托换桩基剩余承载力的影响,并分析了桩基与隧道净距、断桩长度比两个因素.结果 表明:进行断桩处理的既有桩基的承载力发生明显的承载力损失,主要为桩侧承载力损失.实际施工过程中,可根据桩基与隧道净距、断桩长度比确定剩余承载力占比取值区间.

Numerical Analysis of the Influence of Tunnel Excavation on the Bearing Capacity of the Existing Bridge Pile Foundation

Relying on the pile foundation project of Chengdu Metro Line 13 tunnel crossing Jiaozi overpass in short distance, the finite element model is established to study the influence of tunnel excavation on the residual bearing capacity of the underpinned pile foundation and the two factors of net distance between pile foundation and tunnel and length ratio of broken pile are analyzed. The results show that the bearing capacity of the existing pile foundation has obvious bearing capacity loss, mainly the bearing capacity loss of the pile side. In the actual construction process, the ratio interval of residual bearing capacity can be determined according to the net distance between pile foundation and tunnel and the length ratio of broken pile.